In a heavy-ion collision the branching of energetic partons occurs in the presence of a hot, dense and coloured Quark Gluon Plasma (QGP). The interaction between partons in the branching sequence and the QGP results in modifications of both the parton branching pattern and of the QGP they propagate through (see [1]}, [2]}, [3]}, [4]} for reviews).
While all modifications arise from the same underlying dynamics, the exchange of colour and energy-momentum between partons and the QGP, it is helpful to describe qualitatively the classes of modifications as follows.
